The Pass amps are very good.The X series will probably mate better to the paradigms.I believe that if you were to upgrade to one of the others that you mention,it would be worth moving to an XA model.The efficiency and tonal quality will be more revealing.
The area in which you are unsatisfied with is notorious with a "non-preamp" configuration.Using a digital EQ might also remedy your problem,but you have to use good judgement when applying this solution.
The area in which you are unsatisfied with is notorious with a "non-preamp" configuration.Using a digital EQ might also remedy your problem,but you have to use good judgement when applying this solution.